Differential block



A UNITED STATES PATENT OFFICE.

HENRY W. RUSGROVE, OF EVERETT, MASSACHUSETTS, ASSIGNOR TO THE BOSTON AND LOCKPORT BLOCK COMPANY, OF JERSEY CITY, NEW

JERSEY.

DIFFERENTIAL BLOCK.

SPECIFICATION forming part Of Letters Patent No. 485,115, dated October 25, 1892. Application filed June 13, 1892. Serial No. 436,477. (No model.)

T at whom it may concern.-

Be it known that I, HENRY W. RUSGROVE, a citizen of Great Britain, and a resident of Everett, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Differential Blocks, of which the following, taken in connection with the accompanying drawings, is a specification. This invention relates to improvements on the patent granted May 22, 1883, No. 278,078, to Charles F. Batt for a hoisting-pulley, and it is carried out as follows, reference being had to the accompanying drawings, wherein Figure 1 represents a side elevation of the invention. Fig. 2 represents a vertical section on the line X X shown in Fig. 1, showing a portion of the ratchet-wheel broken away; and Fig. 3 represents a cross-section on the line Y Y shown in Fig. 2.

Similar letters refer to similar parts wherever they occur on the different parts of the drawings.

A represents the frame of the block, which may be made of one or more parts, as may be 2 5 most practical and convenient. On a spindle a, secured to such frame, is loosely journaled the chain-pulley B, to which power is applied, as usual, by means of an endless chain pulled in either direction by the operator. The face of the pulley B has a snail or worm B, as usual, which is adapted to actuate a ratchet or toothed gear 0, as shown.

To one side of the ratchet-wheel O is secured or cast in one piece with it the hoisting-pulley C, to which the hoisting-chain is applied in the usual manner.

C" is a spindle on which is journaled the ratchet-wheel C and hoisting-pulley C.

A is the usual suspension swivel-hook.

The above construction is substantially like that shown and described in the patent to Batt above mentioned, and is not claimed as my present invention.

For the purpose of preventing the hoistingchain from disengagement with the hoistingpulley C in lowering the load I arrange above such pulley a loosely-journaled, preferably grooved, roller D, which is free to rotate on a spindle d, attached to the frame of the ma- 5o chine, as fully shown in Figs. 1 and 2.

In a device of this kind it is desirable to employ a brake mechanism under the control of the operator, so as to regulate the descent of the load, and for this purpose I make on one side of the chain-pulley B a brake-wheel or cylindrical shoulder B", as shown in the drawings. In connection with such brake- Wheel I use a yielding or expansive brakeshoe E, which is secured, preferably, at its lower end to the frame A or a bracket thereon, and is normally held out of contact with the brake-wheel by the influence of a spring 6, as shown in Figs. 2 and 3.

A rope or chain may be directly attached to the free end of the brake-shoe E; but in practice I prefer to attach to such free end of the brake-shoe a pivoted link F, having a rope or chain G attached to it to enable the operator to pull downward on it when he desires to put the brake on in lowering the load.

His a pawl secured to a spindle h, journaled in the frame of the device, which pawl is normally in engagement with the ratchet-wheel C for the purpose of preventing the descent of the load until said pawl is raised out of engagement with said ratchet-wheel.

The pawl H and brake-shoe E are preferably conuected for operation as follows: At 2' is pivoted to the frame A a rock-lever I, one end of which is connected to the spring 6 and So the other to a link It, the rear end of which is connected to an arm or projection h on the pawl-shaft h, as fully shown in Fig. 2. The weight of the pawl 11 serves to hold it normally in engagement with the ratchet-wheel C, as shown in Fig. 2. It will thus be seen that by pulling downward on the rope or chain G the pawl H is disengaged from the ratchetwheel and may be held so during the lowering of the load preferably by hooking the link F on a hook or projection A on the frame A, said link F having for this purpose a slotted perforation f, adapted to receive the hook or projection A. An increased strain on the rope or chain G causes the brake-shoe E to be 5 brought against the friction-wheel B" with more or less frictional resistance, by which the speed of the descent of the load can be registered and controlled by the person in charge. If it is desired to suspend the load 10c and hold it in such position for any length of time, it is only necessary to disengage the link F from the hook or pin A" and release the rope or chain G, when the pawl H will drop by its own gravity into engagement with the ratchet-wheel G.

I wish to state that the precise intermediate connecting mechanism as shown between the pawl and the brake-shoe is not essential, as other suitable connecting mechanism may be -used without departing from the spirit of my invention.

L in Fig. 2 is a loosely-rotating toothed wheel and pinion adapted to engage with the ratchet-wheel O for the purpose of distributing a lubricant to the teeth of the ratchetwheel. For this purpose the pinion L is made to rotate in a cup A which contains the lubricant.

The invention is very simple as well as durable in its construction and operation, and by the improved mechanism as described the operator is given aperfect control of the raisin g, lowering, and stopping a load whenever so desired.

Having thus fully described the nature, construction, and operation of my invention, I wish to secure by Letters Patent and claim 1. In a dilferential block or hoisting pulley, the combination, with a pulley-frame, of a driving-pulley having a snail on one face and provided with a cylindrical brake-shoulder, a ratchet-wheel which is rotated by the snail, a hoisting-pulley rotated by the ratchet-wheel, a pawl for engaging the ratchet-wheel, a brake-band for acting on the brake-shoulder of the driving-pulley, and devices for disengaging the pawl from the ratchet-wheel and forcing the brake -band against the said brake-shoulder, substantially as described.

2. In adifferential block or hoisting-pulley, the combination, with a pulley-frame, of a driving-pulley having a snail on one face and provided with a brake-shoulder, a ratchetwheel which is rotated by the snail, a hoisting-pulley at one side of the ratchet-wheel, a pawl pivoted to the pulley-frame to engage the ratchet-wheel, a brake for acting on the said brake-shoulder, means for pressing the brake toward the brake-shoulder, and a rocking lever connected with the pawl and operated by the movement of the brake toward the brake-shoulder to disengage the pawl from the ratchet-wheel, substantially as described.

3. In a differential block or hoisting-pulley, the combination, with a pulley-frame, of a driving-pulley havingasnail on one face and a cylindrical brake shoulder in juxtaposition to the snail, a ratchet-wheel having a hoisting-pulley and rotated by the snail, a pawl engaging the ratchet-wheel and carried by a shaft supported in the pulley-frame, and devices connected with the pawl-shaft for throwing the pawl into and out of engagement with the ratchet-wheel, substantially as de scribed.

4. In a differential block or hoisting-pulley, the combination, with a driving-wheel having a snail and a brake shoulder or wheel and a ratchet-wheel rotated by the snail and having a hoisting-pulley, of a pawl carried by ashaft mounted on the pulley-frame, a brake-band extending round the brake shoulder or wheel,

a rocking lever connected with the pawlshaft and having an elastic connection with the brake-band, and means for moving the brake-band upon the brake shoulder or brake-wheel, substantially as described.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 28th day of May, A. D. 1892.

HENRY W. RUSGROVE.

Witnesses: 4

ALBAN ANDREN, HERBERT LORD. 

